1. Field
Embodiments of the present invention relate to a method of determining a beamforming coefficient, a beamforming method, and an ultrasonic imaging apparatus.
2. Description of the Related Art
An ultrasonic imaging apparatus radiates ultrasonic waves toward a target part inside a target object, for example, a human body from a surface of the target object and then collects reflected ultrasonic waves to acquire a sectional image of various tissues or structures inside the target object, for example, an image of blood flow or a sectional image of soft tissue based on information contained in the collected ultrasonic waves.
The ultrasonic imaging apparatus is relatively small in size, inexpensive, displays an image in real time, and has high stability due to no radiation exposure as compared with an X-ray imaging apparatus, and thus, has been extensively used for diagnosis of the heart, abdomen, and urinary system and in obstetrics and gynecology.
In order to acquire an ultrasonic image, the ultrasonic imaging apparatus performs beamforming to estimate the size of reflected waves of a predetermined space from channel data that is collected by an ultrasonic probe from an ultrasonic echo signal. Beamforming is a process of acquiring an image appropriate for diagnosis of a target object by compensating for a time difference of ultrasonic signals input through each ultrasonic sensor, for example, a transducer, applying predetermined weights to respective ultrasonic signals so as to emphasize a signal at a predetermined position and to relatively attenuate a signal at another predetermined position, and focusing ultrasonic signals.
Beamforming of an ultrasonic imaging apparatus may be classified into data-independent beamforming and adaptive beamforming according to the characteristics of weights used in beamforming and applied respective ultrasonic signals (ultrasonic channels).
The data-independent beamforming uses a weight that is determined regardless of an input ultrasonic signal, and is referred to as fixed beamforming since the weight used therein is not changed.
The adaptive beamforming determines an appropriate weight according to an input ultrasonic signal. According to the adaptive beamforming, a weight may be changed according to the input ultrasonic signal. The adaptive beamforming is referred to as data-dependant beamforming.